Landing sensor for aircraft

Landing sensor for aircraft

In 2017, ROSAS’ aviation engineers participated in a feasibility study for a sensor that can measure stresses and resistances during the landing of a certain type of aircraft. The measurements are used for various purposes by the aircraft's electronic controllers: hard landing detection, aircraft stability control, breaking, health monitoring, etc.

Project and objective

ROSAS’ safety engineers have performed a preliminary system safety assessment (PSSA) of the final sensor architecture according to the SAE ARP4761 aerospace safety standard.

The objective of this work was to perform an initial Fault Tree Analysis FTA of the safety related system functions as part of the safety assessments required for the Preliminay System Safety Assessment PSSA in order to verify the actual Hardware Design Assurance Levels DAL against the given target DAL.

Each landing gear consists of two wheels. Each wheel is attached to a wheel shaft. Then, the wheel shafts are connected to the landing gear by a suspension called a shock absorber. The purpose of the sensor studied is to measure the stress in the wheel shafts and the compression of the shock absorber. Its purpose is to measure the following parameters on each of the landing gears:

• The resistance on each shaft to which a wheel is attached
• The compression of the shock absorber
• The torque applied on each shaft to which a wheel is attached (only on the Main Landing Gear).

For this study, it was required to minimise the operating time of the interrogator. Thus, instead of a redundant system, a "control" architecture was proposed.